Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already cover the safety profile (read-only, idempotent, non-destructive, closed-world), so the description does not need to repeat that. It adds use-case context, but does not disclose important conversion assumptions such as whether month/year values use calendar or average durations, nor how rounding is handled; 'Returns: {input}.' is not useful behavioral detail.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The first sentence is front-loaded and defines the operation and supported units clearly, and the remaining sentences are compact. The placeholder-like 'Returns: {input}.' is confusing rather than useful, which slightly weakens the structure.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple three-parameter shape, rich annotations, 100% schema coverage, and an output schema, the description is close to sufficient. However, for a time conversion tool, the ambiguous month/year basis and rounding behavior are material gaps that the description does not address.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the from/to parameters have enums, so the schema already fully documents value, from, and to. The description restates the inputs and units but adds no additional format constraints, edge-case meaning, or conversion rules beyond what the schema provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Convert') and resource ('time') and enumerates the supported units, making the tool's purpose unmistakable. It does not distinguish this tool from close siblings such as calculate_time_difference, calculate_add_hours, or the other convert_* tools beyond a generic list_bundles pointer, so it falls short of a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives broad use cases ('project planning or unit homogenization') and points to list_bundles for related calculators, which provides some implied guidance. However, it never states when not to use this tool or which sibling handles adjacent operations such as adding hours, computing time differences, or converting time zones.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.